GUI: refuse to close the preferences if any of the actions to execute is invalid

src/mkvtoolnix-gui/main_window/preferences_dialog.cpp

@@ -18,6 +18,7 @@
 #include "mkvtoolnix-gui/main_window/prefs_run_program_widget.h"
 #include "mkvtoolnix-gui/merge/additional_command_line_options_dialog.h"
 #include "mkvtoolnix-gui/util/file_dialog.h"
+#include "mkvtoolnix-gui/util/message_box.h"
 #include "mkvtoolnix-gui/util/model.h"
 #include "mkvtoolnix-gui/util/side_by_side_multi_select.h"
 #include "mkvtoolnix-gui/util/widget.h"
@@ -826,4 +827,31 @@ PreferencesDialog::showPage(Page page) {
   ui->pages->setCurrentIndex(pageIndex);
 }
 
+void
+PreferencesDialog::accept() {
+  for (auto tabIdx = 0, numTabs = ui->twJobsPrograms->count(); tabIdx < numTabs; ++tabIdx) {
+    auto tab   = qobject_cast<PrefsRunProgramWidget *>(ui->twJobsPrograms->widget(tabIdx));
+    auto error = tab->validate();
+
+    if (error.isEmpty())
+      continue;
+
+    showPage(Page::RunPrograms);
+    ui->twJobsPrograms->setCurrentIndex(tabIdx);
+
+    Util::MessageBox::critical(this)
+      ->title(QY("Invalid settings"))
+      .text(Q("<p>%1 %2</p>"
+              "<p>%3</p>")
+            .arg(QY("This configuration is currently invalid.").toHtmlEscaped())
+            .arg(error.toHtmlEscaped())
+            .arg(QY("Either fix the error or remove the configuration before closing the preferences dialog.").toHtmlEscaped()))
+      .exec();
+
+    return;
+  }
+
+  QDialog::accept();
+}
+
 }}

src/mkvtoolnix-gui/main_window/preferences_dialog.h

@@ -68,6 +68,8 @@ public slots:
   void enableOftendUsedCountriesOnly();
   void enableOftendUsedCharacterSetsOnly();
 
+  virtual void accept() override;
+
 protected:
   void setupPageSelector(Page pageToShow);
   void setupToolTips();

src/mkvtoolnix-gui/main_window/prefs_run_program_widget.cpp

@@ -436,4 +436,10 @@ PrefsRunProgramWidget::showPageForType(Util::Settings::RunProgramType type) {
   d->ui->gbTypeSpecificSettings->setVisible(d->pagesByType[type] != d->ui->emptyTypePage);
 }
 
+QString
+PrefsRunProgramWidget::validate()
+  const {
+  return config()->validate();
+}
+
 }}

src/mkvtoolnix-gui/main_window/prefs_run_program_widget.h

@@ -26,6 +26,7 @@ public:
 
   bool isValid() const;
   Util::Settings::RunProgramConfigPtr config() const;
+  QString validate() const;
 
 signals:
   void titleChanged();

src/mkvtoolnix-gui/util/settings.cpp

@@ -37,12 +37,18 @@ defaultUiFont() {
 
 }
 
+QString
+Settings::RunProgramConfig::validate()
+  const {
+  return (m_type == RunProgramType::ExecuteProgram) && (m_commandLine.isEmpty() || m_commandLine.value(0).isEmpty()) ? QY("The program to execute hasn't been set yet.")
+       : (m_type == RunProgramType::PlayAudioFile)  && m_audioFile.isEmpty()                                         ? QY("The audio file to play hasn't been set yet.")
+       :                                                                                                               QString{};
+}
+
 bool
 Settings::RunProgramConfig::isValid()
   const {
-  return m_type == RunProgramType::ExecuteProgram ? !m_commandLine.value(0).isEmpty()
-       : m_type == RunProgramType::PlayAudioFile  ? !m_audioFile.isEmpty()
-       :                                            true;
+  return validate().isEmpty();
 }
 
 QString

src/mkvtoolnix-gui/util/settings.h

@@ -114,6 +114,7 @@ public:
     unsigned int m_volume{75};
 
     bool isValid() const;
+    QString validate() const;
     QString name() const;
 
   private: